i actually think the results in south carolina suggest that biden should drop, as he didn't demonstrate the kind of dominance that he needed to.
but, i also think this regional showdown is necessary - i think it's imperative that biden get smacked around a little in the midwest to get the point across to southern voters that he's not going to win there, whether they like it or not, and send the message to stop voting for a candidate that isn't going to win.
at the end of the day, it's far more important to be competitive in new hampshire than it is to be competitive in south carolina.